生成的验证码：
/**
* 以图片的形式生成验证码并保存至本地文件中
**/
public class demo {
public static String[] character = {"A","B","C","D","E","F","G","H"};public static int width = 90;
public static int height = 30;
public static int CHAR_WIDTH = 16;
public static int CHAR_HEIGHT = 20;
public static void main(String[] args) throws IOException{
BufferedImage buffImage = new BufferedImage(width,height, BufferedImage.TYPE_INT_RGB);
Graphics gd = buffImage.getGraphics();
gd.setColor(Color.CYAN);
gd.fillRect(0, 0, width, height);
Font font = new Font("宋体", Font.BOLD, 18);
gd.setFont(font);
gd.setColor(Color.BLACK);
Random random = new Random();
/* 随机生成多条扰乱视线的线条 */
for(int i =0;i<10;i++){
int x = random.nextInt(width);
int y = random.nextInt(height);
int x1 = random.nextInt(width);
int y1 = random.nextInt(height);
gd.drawLine(x, y, x1, y1);
}
StringBuffer buff = new StringBuffer();
for(int i =0 ; i<5;i++){
if(random.nextBoolean()){
int num = random.nextInt(10);
buff.append(String.valueOf(num));
setRGB(String.valueOf(num),random, gd,i);
}else{
String tm = character[random.nextInt(character.length)];
buff.append(tm);
if(random.nextBoolean()){
setRGB(tm,random,gd,i);
}else{
setRGB(tm.toLowerCase(),random, gd,i);
}
}
}
/** 查找自己系统可查看的图片格式 **/
// String[] names = ImageIO.getWriterFormatNames();
// for(int i =0;i<names.length ;i++){
// System.out.println(names[i]);
// }
System.out.println(buff);
ImageIO.write(buffImage,"jpeg" , new File("H:/temp.jpeg"));
}
/** 在写字体前，修改画笔的颜色 **/
public static void setRGB(String str,Random random,Graphics g,int i ){
int red = random.nextInt(256);
int green = random.nextInt(256);
int blue = random.nextInt(256);
g.setColor(new Color(red, green, blue));
/** 位置控制 **/
g.drawString(str, CHAR_WIDTH*i+4, CHAR_HEIGHT);}
}